Mr Khan said: "For too long, London taxpayers have had to bear the brunt of Boris Johnson's appalling botched water cannon deal. This has been another waste of taxpayers' money by Boris Johnson.

"Londoners continue to live with his vanity.

"I am pleased we have managed to finally get rid of them and I made an election promise to Londoners that I would claw back as much of this cash as possible, and pump it into helping young people at risk of being affected by crime and giving them better life opportunities."

Image:Boris Johnson bought the vehicles four years ago

A source close to the former foreign secretary said: "Boris made tackling crime his number one priority when he came into office in 2018.

"During his time as mayor he reduced the murder rate by 50% and brought overall crime down by 20%. This is a legacy the new mayor has sadly been unable to match."